The invention relates to a telephone apparatus including a loudspeaker and a microphone; a speech transmission network, that on the one side is coupled to the loudspeaker and the microphone and on the other side can be coupled to the telephone lines; and a modem having an input and an output.
Such a telephone apparatus is known from the Swiss patent 663305. Including a modem in a telephone apparatus in accordance with said publication has the advantage that circuits that are common to conventional stand alone modems and conventional telephones for voice communication, can be used in common instead of being provided twice. Such common circuits for example are the speech transmission network, the circuit to adapt the telephone or modem to the telephone lines and the keypad for the selection of numbers.
In the telephone apparatus according to the above mentioned Swiss patent a switch is provided to couple either the handset, comprising the microphone and the loudspeaker, or the modem with the speech transmission network. Such a switch commonly is in the form of a relay, which relay is a relatively expensive component in relation to the other components of a telephone apparatus.